1. Field of the Invention
The present invention relates generally to electric motors and, more particularly, to electric motors comprising permanent magnets. Specifically, one embodiment of the present invention provides a high-efficiency motor comprising two sets of permanent magnets and further comprising electromagnets incorporated to be energized by a control system to provide a variable-speed motor that produces high torque and a method for providing a high-efficiency, variable-speed permanent magnet motor that produces high torque.
2. Description of the Prior Art
Known electric motors employ an electrical current to generate a magnetic field that interacts with another magnetic field to induce motion. There are two physical components for all electric motors, the armature, or rotor, which moves and the stator which is stationary. Known technologies for electric motors generally fall into two categories, fully-powered and a powered/passive combination. For a fully-powered motor an electrical current is used to generate the magnetic fields for both the armature and stator. A combination motor incorporates permanent magnets to supply one of the magnetic fields, and an electrical current generates the other. Combination motors are typically operated from a DC power source.
An electric/magnetic motor works by utilizing the magnetic attraction/repulsion between magnetic fields that are from the rotor and stator. When these two fields are directly opposite from each other, and magnetically centered, there is the maximum attraction between the two fields, but no torque is being applied to the armature. To induce motion/torque into the armature, the magnetic centers must be offset from each other to induce torque into the armature.
Electric motors and/or generators based on two sets of permanent magnets and having no external power source have been attempted since at least the 1920's. So far they have been unsuccessful. Most of the magnetic arrangements have the armature with one polarity, “North,” for example, and the stator has the opposite polarity, “South,” for this example. There are two types: what can be referred to as “Type One” is based on perfectly balanced magnetic fields having no discernable magnetic drag, while “Type Two” consists of a series of magnetic flux concentrations with reduced flux between the peaks. Both of these types will keep spinning for many hours slowly loosing momentum and finally stop. This decay is very slow and not perceptible to the eye over the short term. The Type One model has a uniform flux field between the armature and stator with complete balance. The Type Two model steps from one flux peak to another with the force required to exit one flux peak balancing with the force of attraction when entering into the next flux peak, but it is still magnetically balanced. The magnetic field entry force and the magnetic field exit force are of equal magnitude but of opposite polarity.
It would be desirable to provide a motor that overcomes the disadvantages of known attempts at motors that comprise two sets of permanent magnets. More particularly, it would be desirable to provide such a motor that can be controlled to provide high torque at variable speed with high efficiency.